In recent years, when semiconductors, particularly solar batteries are produced, a method in which a layer containing an impurity-diffusing component referred to as dopant (diffusing agent composition layer) is formed using an ink-jet system has been employed. This method has been expected to contribute to reduction of the production cost since easy pattern formation is enabled without need of a complicated step as compared with conventionally employed lithographic methods and the like. In particular, by using ink-jet printing, a diffusing agent composition can be coated only onto a desired site, and thus significant reduction of the amount of the diffusing agent composition used is enabled as compared with conventionally employed methods of coating a diffusing agent composition such as a spin coating method.
Accordingly, by using an ink-jet system, an operation to form a pattern is facilitated, and the amount of the diffusing agent composition used can be reduced. However, conventional diffusing agent compositions containing ethanol or isopropyl alcohol as a principal component are disadvantageous in discharge stability due to too rapid drying characteristics which result in clogging at a head portion, and the like. In this regard, a method for further improving discharge stability of a diffusing agent composition was proposed in which prevention of clogging, etc., is enabled by adding 20 to 40% by volume of glycerin and dimethyl formamide (DMF) to a conventional diffusing agent compositions containing ethanol or isopropyl alcohol as a principal component (Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2005-038997